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Author Topic: 12-14v from motorcycle... @ Vin  (Read 520 times)
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So I hooked up my project for a quick test of the display to my bikes power- worked great for a 20 second test (just running through the numbers on my 7-seg display) .

Was happy with the results so I unplugged it all and went inside. Go to plug my arduino into the computer- nothing. power led is on, green usb led is, and yellow tx led is on- all just solid... but nothing happens... computer doesn't see it at all.

I pick it up to see if the plug is not seated well- and HOLY crap the 32u4 is scorching hot...

What happened? Is this toast?


EDIT- im only posting this because the spec says the limit is 20 volts-

http://arduino.cc/en/Main/ArduinoBoardMicro

I am 99% positive that i didn't even exceed 12.5volts- i never had the bike even turned on (When i know it throws 14.1 or so) - and if i did exceed 12 volts- it wasn't for more than half a minute...

I suppose I just need to invest in some of these https://www.sparkfun.com/products/107 or similar (maybe this http://www.radioshack.com/product/index.jsp?productId=12669026&filterName=Category&numProdsPerPage=60)

I apologize I am total newb at this- feel like I got into this stuff on the wrong angle... i can program but Im really just learning the electrical stuff...
« Last Edit: April 20, 2013, 09:59:48 am by pcguru000 » Logged

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You haven't provided a wiring diagram to show how you connected it to your motorbike so how can we give you any useful advice.

...R
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As I said- its really simple, just a straight soldered pair of wire (ground, power) to the Vin and Gnd on my board (I have the duino mounted on some female mobo headers so i can pull it off if i want)

The rest of the wiring is just basic LOW or HIGH digital pins, and a 3.3 v line to drive the common anode 7 segment.

It's so brutally simple I cant imagine how it went wrong- i mean it worked perfectly on the bike.

Bike 12v -> Duino Vin
Bike Gnd -> Duino Gnd

Duino 3.3v - > Common Anode 7-Seg
Duino Digital Pins 2-8 -> 7-Seg

Nothing more :/ - worked great before from my PC too. just guessing the 12v from the bike fried it somehow... Does this happen?
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I'm guessing you can supply power at up to 20v into the power socket but I'm not sure you can connect 20v to the Vcc pin. My guess is there is a voltage regulator between the power socket and the Vcc pin.

If you did connect 12v to a 5v pin ... well ...

...R
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I'm surprised the Arduino chip got so hot, it's usually the v.reg chip, eg
(14V-5V)*100mA = 0.9 Watts, and maybe more considering you're driving
7 or more Leds.

Besides going to a "real" v.reg [as opposed to those teensey-weensey smt things],
you might just try using something in series in the Vin line to provide an IR drop.
Eg, a fat resistor or a 5 Watt, 5-8V Zener diode. Either one will get somewhat warm,
but will move the heat off the Arduino board.
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